Cooling and ventilation of a high-speed ground transportation system.

This paper presents the special needs and difficulties concerning cooling and ventilation of the SwissMetro high-speed ground transportation system. SwissMetro is based on four complementary technologies: a complete underground infrastructure, a partly evacuated tunnel system to reduce the aerodynamic drag of the vehicle with a maximum speed between 400 and 500 km/h, linear electric motors and a magnetic levitation and guiding system. Due to high internal and external heat loads permanent cooling and air-conditioning of the vehicle is required. Additional thermal problems may occur in the case of an emergency. The pressure level inside the tunnel has to be raised within a short period of time to guarantee the safety of the passengers and to avoid any health risks. This repressurization of long tunnel sections may cause shock waves and high temperatures inside the tunnel. The aim of the project is to analyse the spatial and temporal temperature evolution in the SwissMetro tunnels under different operating conditions and in emergency situations.